The field of the invention is the battery art, and more particularly that of sealed cells for use in outer space.
The loss of electrolyte from the useable areas between the electrodes of an electrochemical cell to the walls and void spaces of the cell container are well known. It is also well known that the retention of sufficient electrolyte in a cell electrode stack is critical to maintaining performance of the cell during electrical cycling, such as that occurring in a spacecraft during orbiting.
Various materials have been tried for external (to the electrode stack) wisks such as polypropylene felt, asbestos paper, and zirconium oxide cloth. Generally, the prior art materials and structures have been of questionable permanent wettability or mechanical fragility. Particularly, the nylon (e.g., Pellon 2505) and polypropylene (e.g., Raiwex 1242) materials tend to dry out quite readily in comparison with the electrodes.
The best known prior art is that contained in U.S. Pat. Nos. 3,333,986 to patentees Chreitzberg et al; 3,615,845 to patentee Gray, and 4,004,067 to patentees Briggs et al.